1. Field of the Invention
The present invention relates to an umbrella, and more particularly to an umbrella structure that can be folded and unfolded automatically by using one hand.
2. Brief Description of the Related Art
At early stage, a user needs to hold a handle of an umbrella and push a link rod upward by extending another hand into umbrella ribs, such that a canopy is spread open with the umbrella ribs in order to use the umbrella, and then the user needs to pull the link rod downward for folding the umbrella after use. Since the process of folding or unfolding the umbrella of this sort requires operations of both hands, it may cause problems or inconvenience to the user who is holding other objects with one hand, or whose hand is injured. Therefore, an automatic folding/unfolding umbrella that requires one-hand operation was introduced into the market.
Although some conventional umbrellas requiring one-hand operation can be folded and unfolded automatically, yet the structure and operation of these umbrellas still require further improvements. The automatic folding/unfolding umbrellas as disclosed in the following patents are given as examples to show that there is a need for improvements.
1. An automatic foldable umbrella as disclosed in R.O.C. Pat. No. 283,319 only requires one hand for the operation of the umbrella to achieve the automatic folding and unfolding effects. However, this umbrella requires an inner tube retracted into an outer tube first, and then a latch is released to eject a spring installed in the inner tube in order to unfold the umbrella. In other words, this umbrella still requires both hands for operating the umbrella and causes inconvenience to the folding and unfolding operation of the umbrella.
2. An umbrella with an automatic folding and unfolding structure as disclosed in R.O.C. Pat. No. I317,269 can be operated by one hand to achieve the automatic folding and unfolding effect, but the umbrella adopts a two-section pressing design for folding and unfolding the umbrella. If the user wants to unfold the umbrella again, the spring has to restore its original compressed condition, so that the operation of the umbrella still requires both hands and also incurs problems and inconvenience to the user.
3. An automatic umbrella device (II) as disclosed in R.O.C. Pat. No. 454,462 can be operated by one hand to achieve the folding and unfolding effects, but the principle of operating the umbrella is unlike the general habit of using the umbrella. As to its structure, the total weight of this umbrella is heavier than the weight of the general umbrellas, so that this umbrella is still inconvenient to use.
4. An improved umbrella control device as disclosed in R.O.C. Pat. No. M305,601 allows an umbrella to be operated by one hand to achieve the folding and unfolding effects, yet the operation of folding or unfolding the umbrella is controlled simply by a coiling wire with a sufficient length, and it takes some effort to pull a link rod by the coiling wire, so that this umbrella is still inconvenient to use.
5. An automatic folding/unfolding umbrella with a clutch device as disclosed in R.O.C. Pat. No. 283,319 and an automatic foldable umbrella as disclosed in R.O.C. Pat. No. 571,657 and an automatic folding and unfolding umbrella as disclosed in R.O.C. Pat. No. 578,471 can be operated by one hand to achieve the automatic folding and unfolding effects, but these three types of umbrellas have complicated components, not only incurring a higher cost, but also having a significantly higher damage rate of components and a higher level of difficulty for repair and maintenance.
In each of the foregoing prior arts, the umbrella structure comes with complicated components, inconvenient operations, and high cost. Obviously, each prior art requires a main rod, and a link rod base linked to a link rod, wherein the slide stroke for folding or unfolding the umbrella exceeds half of the length of the main rod, meaning that the link rod base requires a long slide stroke and thus takes relatively longer time to fold or unfold the umbrella, and requires more effort to drive the umbrella by one hand.